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A104148
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Difference between n^3 and largest m less than n^3, where m > 0 is either a prime or a square.
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1
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1, 2, 3, 4, 5, 6, 3, 2, 3, 4, 5, 18, 3, 2, 3, 4, 5, 2, 7, 4, 9, 4, 17, 6, 3, 2, 9, 10, 7, 2, 7, 4, 3, 12, 7, 2, 3, 38, 3, 4, 11, 14, 25, 4, 9, 10, 5, 6, 9, 4, 5, 4, 7, 12, 15, 4, 9, 22, 17, 38, 7, 4, 5, 16, 5, 2, 9, 28, 11, 28, 17, 14, 3, 28, 9, 4, 5, 12, 3, 58, 5
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OFFSET
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2,2
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LINKS
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FORMULA
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EXAMPLE
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a(5) = 4 because largest square less than 5^3 is 121 and 125 - 121 = 4.
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MATHEMATICA
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lst = {}; Do[k = n^3; a = NextPrime[k, -1]; b = Floor@Sqrt[k - 1]^2; AppendTo[lst, k - Max[a, b]], {n, 2, 82}]; lst (* Arkadiusz Wesolowski, Jun 03 2013 *)
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PROG
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(Magma) [n^3-Maximum(Isqrt(n^3-1)^2, PreviousPrime(n^3)): n in [2..100]]; // Bruno Berselli, Jun 03 2013
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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